A known conventional filling and packaging machine of this type includes a container vertically adjusting device that vertically adjusts a bottomed cylindrical container body made of synthetic resin, which is supplied in an arbitrary orientation, such that an upper end opening thereof faces up and supplies the bottomed cylindrical container body to a subsequent process, a filling device that fills the container supplied from the container vertically adjusting device with contents, a lid supplying device that covers the upper end opening of the container, which is filled with the contents, with a lid substantially C-shaped in cross section, and a sealing device that heats the lid and seals the container upper opening with the lid (see for example, Patent Document 1).
After peeling the lid of the bottomed cylindrical container body made of synthetic resin, a consumer sometimes directly puts his/her mouth on the container opening and drinks the contents. Therefore, in order to keep the periphery of the container opening sanitary, in the bottomed cylindrical container body made of synthetic resin, a lid configured to protect this portion, i.e., a lid (substantially C-shaped in cross section) consisting of a disc-like lid body that covers the container upper end opening and a skirt provided to be suspended from a lid body peripheral edge is used.
A known filling and packaging machine for producing the contents-filled container covered with the lid substantially C-shaped in cross section pays attention to excellent moldability and shape retainability of an aluminum foil, and includes a lid punching and molding device that uses a sheet-like lid material obtained by laminating a heat seal layer and the like on the aluminum foil, punches a disc-like lid from the lid material, and molds the disc-like lid into a lid substantially C-shaped in cross section immediately after the punching, and a lid supplying device that supplies the molded lid substantially C-shaped in cross section to an opening of the container being conveyed and covers the opening with the lid (see for example, Patent Document 2). However, a metal detector for inspecting an entire product cannot be used on the container including such a lid material having the aluminum foil layer as a base material. Therefore, the problem is that it is not possible to detect metals that may be mixed in the contents such as a nail, a staple, a broken piece of a molded product punching blade, a bolt and a nut, a wire, and a spring. Such containers including the aluminum lids have a drawback in that it is necessary to separately collect the aluminum lid and the container body made of synthetic resin such as polystyrene, which leads to a poor recyclability.
On the other hand, in order to solve such a problem, the present inventors have proposed, as a substitute for the lid material including the aluminum foil layer, a lid consisting of a laminated film including only a synthetic resin layer and not including an aluminum foil layer (see for example, Patent Document 3). Such a lid advantageously consists of a combination including only the synthetic resin layer and highly-developed lid shape. The problems, however, are that a lid material has to be heated and molded in order to form the lid, a lid material forming device is expensive and bulky and, in terms of temperature management of a heating zone for heating the lid material, it is difficult to combine a lid molding device with a filling and packaging machine in a continuous process.
Therefore, in order to solve the problem, the present inventors repeatedly conducted researches on lid materials and succeeded in the development of a lid material made of synthetic resin that can be molded by cold drawing (see for example, Patent Document 4). The present inventors have proposed a container in which such a lid material made of synthetic resin that can be molded by the cold drawing is used, i.e., a sealed container including a resin container and a lid fixedly attached to the resin container in which the lid is obtained by cold-molding a polystyrene resin sheet with propagation energy equal to or larger than 0.015 J in a sheet having thickness of 150 μm measured by a falling weight impact test method conforming to ASTM D3763 and has shape retainability (see for example, Patent Document 5). The present inventors have proposed a sealed container including a resin container and a lid fixedly attached to the resin container in which the lid is produced by cold-molding a resin sheet for cold molding including a base material layer containing polystyrene resin containing high impact polystyrene (HIPS) or a composite consisting of high impact polystyrene and styrene-butadiene copolymer and has shape retainability (see for example, Patent Document 6).
Further, using the lid made of synthetic resin obtained by the cold molding and in order to obtain a product container equivalent to a conventional product container whose lid material including the aluminum foil layer as the base material, the present inventors have proposed a lid molding device including squeezing means or squeezing/twisting means for a lid skirt of a sealed container (see Patent Document 7).